1. Field of the Invention
This invention relates to an IC socket for obviating an electrical connection failure by removing oxidation films with which the surfaces of lead terminals of an IC package are covered.
2. Description of Related Art
An open top type of IC socket in prior art has a structure such as that shown in FIG. 1. In this figure, reference numeral 1 represents an IC socket body; 2 a cover urged upwardly by a resilient member, not shown, and mounted to the IC socket body so as to be able to move vertically; and 2a a cam surface of the cover 2. Reference numeral 3 denotes a plurality of contact pins arranged in the socket body 1; 3a an engaging portion of each contact pin 3; 3b a contact portion of each contact pin 3; and 3c a spring portion of each contact pin 3. Numeral 4 designates an IC package and 5 designates lead terminals of the IC package 4.
Thus, in the conventional IC socket, when the cover 2 is pressed downwardly, the cam surface 2a of the cover 2 acts on the engaging portion 3a of each contact pin 3 so that the upper section of the contact pin 3 including the contact portion 3b moves in an outward direction relative to the IC socket body 1. This allows the IC package 4 to be mounted on the IC socket body 1. Subsequently, when the pressure of the cover 2 is relieved after the mounting of the IC package 4, the contact portion 3b returns to its original position by virtue of a resilient bias force of the spring portion 3c and comes in contact with each of the lead terminals 5 of the IC package 4 in such a manner as to press it down. In this process, the contact portion 3b slides slightly on the surface of each lead terminal 5 and removes an oxidation film with which the surface of the lead terminal 5 is covered, thus providing the electrical connection between the contact pin 3 and the lead terminal 5.
The distance over which the contact portion 3b slides, however, is very short, and therefore the oxidation film with which the surface of the lead terminal 5 is coated cannot be securely removed. This often causes the failure of the electrical connection between the lead terminal 5 and the contact portion 3b. Further, since the contact portion 3b is constructed so that its slide distance is very short, cases have arisen In which it does not entirely slide on the lead terminal 5.